substantial.

1. Large enough in amount or extent to matter.

2. Strongly built or supported rather than flimsy or insubstantial.

Use it for

Words that belong together

• substantial increase
• substantial investment

On the page

The project required a substantial investment in training.

Usage notes

Primary category: academic / formal. Forms: Comparative more substantial; superlative most substantial when comparison is meaningful. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Commonness: moderately common.